NPS Photo

Looking south from Fossil Gulch

Hagerman Fossil Beds National Monument, known mostly for its fossils from the late Pliocene and Pleistocene epochs, contains one of the world’s richest known deposits of fossil horses, Equus simplicidens, thought to be a link between prehistoric and modern horses.

In 1988, the Hagerman horse became Idaho’s state fossil and Hagerman Fossil Beds became a national monument. The Monument contains the Hagerman Horse Quarry, a national natural landmark, recognized as one of the six most important sites in the world regarding the fossil history of horses.

Hagerman Fossil Beds is nationally and internationally significant for its world-class paleontological resources. It includes the world’s richest fossil deposits, in quality, quantity, and diversity, from the late Pliocene epoch. Many of its fossils represent the last vestiges of species that existed before the last Ice Age, the Pleistocene, and the earliest ‘modern’ flora and fauna.

The Monument’s paleontological resources are contained in a continuous, undisturbed stratigraphic record spanning at least 500,000 years. The fossils deposited here appear to represent an entire paleontological ecosystem with a variety of habitats such as wetland, riparian, and grassland savanna.

The Monument is also one of three National Park system units containing a portion of the Oregon Trail National Historic Trail.